Steer Performance, Intake, Digesta Kinetics, and Pasture Productivity of Flaccidgrass at Each of Three Forage Masses

Abstract

‘Carostan’ flaccidgrass (Pennisetum flaccidum Griseb.) is a perennial, warm‐season grass with potential in forage systems for the mid‐Atlantic region. Using established flaccidgrass pastures, we estimated steer (Bos taurus) average daily gain (ADG), stocking rate, and pasture productivity in a 4‐yr experiment. Pastures were continuously and variably stocked at a forage mass (FM) of 1895 (Short), 4186 (Medium), and 5297 (Tall) kg ha−1 (linear; P < 0.01). Steer ADG was similar among FM (mean = 0.65 kg d−1). The Short was stocked at 8.3 steers ha−1 and numbers decreased linearly (P < 0.01) to 7.2 steers ha−1 for Tall. Animal days ha−1 decreased linearly (P < 0.01) from 963 (Short) to 756 (Tall). Weight gain ha−1 did not vary significantly (P = 0.14). Effective feed units (kg ha−1) declined linearly (P = 0.02) from 3756 for the Short to 2842 for Tall. Analysis of digesta kinetics revealed no differences among FM in rate of passage, retention time of liquid or solid phases, fill, or fecal output. Diets selected by steers among FM were similar in concentration of in vitro dry matter disappearance (mean = 690 g kg−1); however, CP declined linearly (P = 0.03) while NDF increased (P = 0.01) with increasing FM. Steer ADG was greater (P = 0.03) in Period 1 (0.77 kg d−1 up to early July) compared with Period 2 (0.53 kg d−1 after early July) and attributed to greater forage quality in Period 1. Flaccidgrass is a productive, perennial forage that can provide quality pasture during the summer.